1. Field of the Invention
The present invention relates to a screen having a projection surface on which a light beam irradiated by an optical equipment such as a projector is irradiated to form a projection image.
2. Description of Related Art
Conventionally, an optical equipment such as a projector which has an optical modulator for modulating a light beam irradiated by a light source in accordance with image information and projects the light beam modulated by the optical modulator in an enlarged manner has been widely used for presentation purpose etc.
The light beam irradiated by the optical equipment is projected on a projection surface of a screen to form a projection image in an enlarged manner, so that presentation before large number of audience can be efficiently conducted.
When the light beam irradiated by such optical equipment is projected on the projection surface of the screen, there may be trapezoidal distortion on the projection image formed on the projection surface if the optical equipment is not correctly positioned relative to the screen. For instance, when the projection surface is inclined in vertical direction relative to optical equipment such as a projector, originally rectangular projection image is trapezoidally distorted where the upper side or the lower side of the rectangle is lengthened. When the projection surface is inclined in horizontal direction relative to optical equipment, trapezoidal distortion where left or right side is lengthened is caused on the image.
Such distortion can be corrected by adjusting the position of the screen, however, so great size of screen is required for displaying large image that it is difficult to manually adjust the position of the screen and, if the position is to be manually adjusted, minute adjustment of the position of the projection surface is difficult.
Accordingly, a projector has been recently developed, where software for converting image signal inputted to optical modulator to correct trapezoidal distortion when the trapezoidal distortion is generated on the image is installed in a controller of the projector.
Such projector is capable of minutely modifying the profile of the optical image irradiated by the projector with the use of the trapezoidal-correction software of the projector to form appropriate rectangular projection image on the projection surface.
However, since such projection-side correction is conducted by forming a trapezoidal image without utilizing a part of rectangular image formation area of the optical modulator and projecting the trapezoidal image on the projection surface to form the rectangular projection image, the entire image formation area cannot be efficiently utilized.
Further, since such software has to be installed on an optical equipment such as a projector, the production cost of the projector is likely to be increased.